An acoustic air data sensing system includes an acoustic transmitter, a plurality of acoustic receivers, and a skin friction sensor. The acoustic transmitter is located to transmit an acoustic signal into airflow about an exterior of a vehicle. Each of the acoustic receivers is located at a respective angle from a wind angle reference line and a respective distance from the acoustic transmitter. The skin fiction sensor is positioned in a boundary layer region of the airflow that interacts with the acoustic receivers and transmitter. Based on time of flight values of the acoustic signal from the transmitter to each of the receivers and a skin friction measurement from the skin friction sensor as inputs to a transformation matrix, the acoustic air data sensing system outputs, from the transformation matrix, the true airspeed, the relative wind angle, and the speed of sound for operational control of the vehicle.

A method of measuring the speed of a fluid, comprising the successive steps of: causing the processor component to emit at the same emission time both a first electrical excitation signal that is applied as input to a first transducer and also a second electrical excitation signal that is applied as input to a second transducer, such that the first transducer generates a first ultrasonic signal and such that the second transducer generates a second ultrasonic signal; putting the processor component on standby; reactivating the processor component after a predetermined standby duration; causing the first ultrasonic signal to be acquired by the second transducer and then by the processor component, and causing the second ultrasonic signal to be acquired by the first transducer and then by the processor component; using a value DToF to estimate the speed of the fluid.

An apparatus for measuring a parameter of a fluid flow passing within a pipe is provided. The apparatus includes a sensing device and a processing unit. The sensing device has a sensor array that includes at least one first macro fiber composite (MFC) strain sensor disposed at a first axial position, and at least one second MFC strain sensor disposed at a second axial position. The first axial position and the second axial position are spaced apart from one another. The at least one first MFC strain sensor and the at least one second MFC strain sensor are both configured to produce signals representative of pressure variations of the fluid flow passing within the pipe. The processing unit is configured to receive the signals from the sensor array and measure one or more fluid flow parameters based on the signals.

A system and method for an aircraft includes a low profile pneumatic sensing system and an acoustic sensing system. The low profile pneumatic sensing system includes a pneumatic sensor positioned to sense first sensed data of an airflow about an exterior of the aircraft and does not extend beyond a boundary layer of the aircraft. The first sensed data is used to determine first air data parameters. The acoustic sensing system is configured to emit acoustic signals about the exterior of the aircraft and sense the acoustic signals as second sensed data. The second sensed data is used to determine second air data parameters.

An angle-of-attack sensor includes at least one acoustic transmitter is configured to provide an acoustic pulse. The first acoustic receiver is positioned at a radial distance from the at least one acoustic transmitter. The first acoustic receiver is configured to receive the acoustic pulse at a first time and provide a first receiver signal. The second acoustic receiver is positioned at the radial distance from the at least one acoustic transmitter aligned with an axis that extends through the at least one acoustic transmitter and the first acoustic receiver. The second acoustic receiver is configured to receive the acoustic pulse at a second time and provide a second receiver signal. The angle-of-attack circuitry is configured to determine a delay difference between the first and second receiver signals representative of a difference between the first time and the second time and determine an angle-of-attack based upon the delay difference.

A transducer system. The system comprises a transducer and circuitry for applying an excitation waveform to excite the transducer during an excitation period. The circuitry for applying has: (i) circuitry for applying a first waveform at a first frequency; and (ii) circuitry for applying a second waveform at a second frequency differing from the first frequency.

A method for measuring a velocity of a fluid, comprising the steps of, acquiring an ultrasonic measuring signal after it has travelled in the fluid over a path of defined length; defining measurement zone of the ultrasonic measuring signal which includes a plurality of measurement lobes; for each measurement lobe, measuring a zero crossing point associated with said measurement lobe; selecting at least two zero crossing points which satisfy a predefined precision criterion; estimating a time of flight for the ultrasonic measuring signal from the selected zero crossing points; utilizing the time of flight to estimate the velocity of the fluid.

A method, apparatus, and system according to which first and second transducers are connected to first and second waveguides, respectively, the first and second waveguides are connected to a pipe, and ultrasonic wave signals are exchanged between the first and second transducers, said ultrasonic wave signals passing through the first and second waveguides, the pipe, and a fluid in the pipe. A temperature of the fluid flowing in the pipe may exceed about 600 C. The first and second waveguides insulate the first and second transducers from the pipe and propagate the ultrasonic wave signals between the pipe and the first and second transducers, respectively, so that the ability of the first and second transducers to exchange the ultrasonic wave signals is not adversely affected by the temperature of the fluid in the pipe. The first and second waveguides may be made of a calcium silicate technical ceramic.

Method for measuring a speed of a fluid and ultrasound fluid meter suitable for implementing this method. The method comprises the step of measuring a travel time taken by a measurement ultrasound signal to travel a path of defined length, the measurement ultrasound signal being generated by a transducer subjected to an excitation electrical signal (16). The excitation electrical signal (16) includes a first signal portion (17) followed by a second signal portion (18). The first signal portion is a periodic signal having a pattern (19) and a decreasing amplitude. The second signal portion is a periodic signal having the same pattern (21) and a constant amplitude.

A system includes a laser air data sensor and an acoustic air data sensor. The laser air data sensor is configured to emit directional light into airflow about an aircraft exterior and to generate first air data parameter outputs for the aircraft based on returns of the emitted directional light. The acoustic air data sensor is configured to emit acoustic signals into the airflow about the aircraft exterior, sense the acoustic signals, and generate second air data parameter outputs for the aircraft based on the sensed acoustic signals.